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authorMika Westerberg <mika.westerberg@linux.intel.com>2016-10-21 17:21:30 +0300
committerLinus Walleij <linus.walleij@linaro.org>2016-10-24 16:33:11 +0200
commitc80f1ba75df25837fb76044e06686b6587d33f6a (patch)
treef39b7fd7795bf25d0d6f19df7a86b57b667c0f06
parent6f7194a10bdba1588357342c6daaaeef98e0004f (diff)
ACPI / gpio: Add hogging support
GPIO hogging means that the GPIO controller can "hog" and configure certain GPIOs without need for a driver or userspace to do that. This is useful in open-connected boards where BIOS cannot possibly know beforehand which devices will be connected to the board. This adds GPIO hogging mechanism to ACPI analogous to Device Tree. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
-rw-r--r--Documentation/acpi/gpio-properties.txt35
-rw-r--r--drivers/gpio/gpiolib-acpi.c71
2 files changed, 106 insertions, 0 deletions
diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt
index 09cff657b82c..d9076af271f5 100644
--- a/Documentation/acpi/gpio-properties.txt
+++ b/Documentation/acpi/gpio-properties.txt
@@ -66,6 +66,41 @@ native:
}
}
+Other supported properties
+--------------------------
+
+Following Device Tree compatible device properties are also supported by
+_DSD device properties for GPIO controllers:
+
+- gpio-hog
+- output-high
+- output-low
+- input
+- line-name
+
+Example:
+
+ Name (_DSD, Package () {
+ // _DSD Hierarchical Properties Extension UUID
+ ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+ Package () {
+ Package () {"hog-gpio8", "G8PU"}
+ }
+ })
+
+ Name (G8PU, Package () {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package () {
+ Package () {"gpio-hog", 1},
+ Package () {"gpios", Package () {8, 0}},
+ Package () {"output-high", 1},
+ Package () {"line-name", "gpio8-pullup"},
+ }
+ })
+
+See Documentation/devicetree/bindings/gpio/gpio.txt for more information
+about these properties.
+
ACPI GPIO Mappings Provided by Drivers
--------------------------------------
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 700ea6ad609b..4f46982ce982 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -857,6 +857,76 @@ static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
}
}
+struct gpio_desc *acpi_gpiochip_parse_own_gpio(struct acpi_gpio_chip *achip,
+ struct fwnode_handle *fwnode, const char **name, unsigned int *lflags,
+ unsigned int *dflags)
+{
+ struct gpio_chip *chip = achip->chip;
+ struct gpio_desc *desc;
+ u32 gpios[2];
+ int ret;
+
+ ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios,
+ ARRAY_SIZE(gpios));
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ ret = acpi_gpiochip_pin_to_gpio_offset(chip->gpiodev, gpios[0]);
+ if (ret < 0)
+ return ERR_PTR(ret);
+
+ desc = gpiochip_get_desc(chip, ret);
+ if (IS_ERR(desc))
+ return desc;
+
+ *lflags = 0;
+ *dflags = 0;
+ *name = NULL;
+
+ if (gpios[1])
+ *lflags |= GPIO_ACTIVE_LOW;
+
+ if (fwnode_property_present(fwnode, "input"))
+ *dflags |= GPIOD_IN;
+ else if (fwnode_property_present(fwnode, "output-low"))
+ *dflags |= GPIOD_OUT_LOW;
+ else if (fwnode_property_present(fwnode, "output-high"))
+ *dflags |= GPIOD_OUT_HIGH;
+ else
+ return ERR_PTR(-EINVAL);
+
+ fwnode_property_read_string(fwnode, "line-name", name);
+
+ return desc;
+}
+
+static void acpi_gpiochip_scan_gpios(struct acpi_gpio_chip *achip)
+{
+ struct gpio_chip *chip = achip->chip;
+ struct fwnode_handle *fwnode;
+
+ device_for_each_child_node(chip->parent, fwnode) {
+ unsigned int lflags, dflags;
+ struct gpio_desc *desc;
+ const char *name;
+ int ret;
+
+ if (!fwnode_property_present(fwnode, "gpio-hog"))
+ continue;
+
+ desc = acpi_gpiochip_parse_own_gpio(achip, fwnode, &name,
+ &lflags, &dflags);
+ if (IS_ERR(desc))
+ continue;
+
+ ret = gpiod_hog(desc, name, lflags, dflags);
+ if (ret) {
+ dev_err(chip->parent, "Failed to hog GPIO\n");
+ return;
+ }
+ }
+}
+
void acpi_gpiochip_add(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
@@ -888,6 +958,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
}
acpi_gpiochip_request_regions(acpi_gpio);
+ acpi_gpiochip_scan_gpios(acpi_gpio);
acpi_walk_dep_device_list(handle);
}